S
M
T
W
T
F
S
26
96°
74°
27
92°
66°
28
88°
65°
29
89°
66°
30
91°
66°
31
95°
64°
1
89°
65°
2
96°
66°
3
95°
62°
4
89°
63°
5
88°
65°
6
87°
63°
7
84°
64°
8
87°
56°
9
88°
56°
10
89°
60°
11
90°
60°
12
89°
59°
13
81°
59°
14
89°
60°
15
88°
59°
16
88°
59°
17
89°
58°
18
88°
59°
19
83°
57°
20
87°
58°
21
88°
59°
22
89°
58°
23
88°
59°
24
88°
59°
25
87°
58°
26
88°
56°
27
85°
58°
28
81°
56°
29
82°
54°
30
83°
57°
31
79°
52°
1
81°
56°
2
81°
54°
3
85°
54°
4
84°
56°
5
77°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Boulder
Boulder's August 2026 forecast shows daily high temperatures ranging from 77° to 96°, with overnight lows between 52° and 74°. The average high for August is 87° with an average low of 60°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Boulder. See also: September | October | November.